The primary purpose of this FIRST award is to examine the relationship of dietary and physical activity factors to wright change following participation in a smoking cessation intervention program. The data on which this project will be based will be obtained from participants in the Chronic Obstructive Pulmonary Disease Prevention Trail (COPD-PT) at the Portland, Oregon, site. Four hundred subjects at this site will participate in an Intensive Smoking Cessation Intervention program and two hundred will be members of a Usual Care control group. The proposed project, which does note overlap with any of the goals of the COPD-PT, will address four issues. First, the relationship of participation in a smoking cessation intervention program to specific and overall changes in food intake will be examined. Second, the relationship of weight change following participation in smoking cessation to reports of change in physical activity level will be explored. Third, the effect of smoking cessation on weight change in more frequent as compared to less frequent smokers will be investigated. Fourth, the natural history of weight change in sustained quitters will be compared to that of continued smokers over a three-year period. This project will contribute to our knowledge of the poorly understood phenomenon of post-smoking cessation weight gain. Although this weight gain is not a risk in itself, it probably serves as a factor inhibiting attempts to stop smoking.